AP Environmental Science — Unit 1: The Living World: Ecosystems

Q1. (ID: ap_environmental_science_MCQ_U1S10Q1)
Which of the following best describes the primary role of producers in an ecosystem?
Q2. (ID: ap_environmental_science_MCQ_U1S10Q2)
As energy flows through an ecosystem, approximately what percentage is typically transferred from one trophic level to the next?
Q3. (ID: ap_environmental_science_MCQ_U1S10Q3)
A grassland ecosystem has a net primary productivity (NPP) of $800 \text{ g C/m}^2/\text{year}$. If a primary consumer population consumes $15\%$ of this NPP and $60\%$ of the consumed energy is lost as waste or respiration, what is the approximate energy available to the next trophic level from this primary consumer population?
Q4. (ID: ap_environmental_science_MCQ_U1S10Q4)
Which of the following organisms would be classified as a primary consumer in most terrestrial food webs?
Q5. (ID: ap_environmental_science_MCQ_U1S10Q5)
Which terrestrial biome is characterized by very cold temperatures, low precipitation, permafrost, and a dominance of mosses, lichens, and dwarf shrubs?
Q6. (ID: ap_environmental_science_MCQ_U1S10Q6)
Which aquatic biome is characterized by rapidly flowing freshwater, high oxygen levels, and organisms adapted to strong currents?
Q7. (ID: ap_environmental_science_MCQ_U1S10Q7)
Which process directly removes carbon dioxide from the atmosphere?
Q8. (ID: ap_environmental_science_MCQ_U1S10Q8)
Nitrification is a crucial step in the nitrogen cycle that involves which of the following transformations?
Q9. (ID: ap_environmental_science_MCQ_U1S10Q9)
In the phosphorus cycle, phosphorus is primarily released from rocks through which process?
Q10. (ID: ap_environmental_science_MCQ_U1S10Q10)
In a desert ecosystem, two species of rodents forage for the same type of seeds. During a period of severe drought, the seed supply becomes critically low. Which of the following is the most likely outcome of this scenario?
Q11. (ID: ap_environmental_science_MCQ_U1S10Q11)
Which of the following processes in the hydrologic cycle is responsible for the formation of clouds?
Q12. (ID: ap_environmental_science_MCQ_U1S10Q12)
Which of the following human activities contributes to an increase in atmospheric carbon dioxide by releasing carbon stored in fossil fuels?
Q13. (ID: ap_environmental_science_MCQ_U1S10Q13)
Gross primary productivity (GPP) refers to the total amount of energy captured by producers. Net primary productivity (NPP) is GPP minus which of the following?
Q14. (ID: ap_environmental_science_MCQ_U1S10Q14)
The arrows in a food web diagram represent the flow of which of the following?
Q15. (ID: ap_environmental_science_MCQ_U1S10Q15)
Which of the following is a key characteristic of a boreal forest (taiga) biome?
Q16. (ID: ap_environmental_science_MCQ_U1S10Q16)
Which of the following aquatic biomes is most likely to experience significant fluctuations in salinity and temperature due to tidal cycles and riverine input?
Q17. (ID: ap_environmental_science_MCQ_U1S10Q17)
Create a simplified world map showing the major terrestrial biomes. Clearly label key biomes such as Desert, Tundra, Tropical Rainforest, Temperate Forest, Taiga, Grassland. Use distinct colors for each biome. The desert regions should be clearly identifiable as hot and dry, covering typical desert areas globally. NO title, NO question text, NO explanatory captions.
Identify the biome characterized by hot temperatures year-round, sparse rainfall, and succulent plants adapted to conserve water.
Q18. (ID: ap_environmental_science_MCQ_U1S10Q18)
Which of the following is the primary energy source for most ecosystems on Earth?
Q19. (ID: ap_environmental_science_MCQ_U1S10Q19)
Create a clear, labeled diagram of the global carbon cycle. Show arrows indicating the movement of carbon between major reservoirs: atmosphere, oceans, land biota (plants/animals), soils, and fossil fuels. Key processes should be labeled with text next to the arrows, including photosynthesis, respiration, combustion, decomposition, and ocean absorption/release. Use distinct colors for reservoirs and arrows. Ensure the arrow representing photosynthesis clearly shows carbon moving from atmosphere to land biota. NO title, NO question text.
Based on the provided diagram of the carbon cycle, which process is primarily responsible for moving carbon from the atmosphere to the biosphere through living organisms?
Q20. (ID: ap_environmental_science_MCQ_U1S10Q20)
In an ecosystem, which trophic level would typically contain organisms that produce their own food using sunlight or chemical reactions?
Q21. (ID: ap_environmental_science_MCQ_U1S10Q21)
Create a simple, generalized ecological pyramid (pyramid of energy) with four distinct trophic levels stacked vertically. The base represents 'Producers', followed by 'Primary Consumers', 'Secondary Consumers', and 'Tertiary Consumers' at the top. Each level should have a label and a numerical value representing a hypothetical energy amount. For example, Producers: 10,000 kcal, Primary Consumers: 1,000 kcal, Secondary Consumers: 100 kcal, Tertiary Consumers: 10 kcal. The pyramid should visually represent the decrease in energy at higher levels. NO title, NO question text.
A food pyramid shows that primary producers have $10,000$ kcal of energy. If the average energy transfer efficiency between trophic levels is $10\%$, how much energy would be available to tertiary consumers?
Q22. (ID: ap_environmental_science_MCQ_U1S10Q22)
Competition between two species occurs when they both require the same limited
Q23. (ID: ap_environmental_science_MCQ_U1S10Q23)
Create a simple, clear food web diagram for a terrestrial ecosystem. Include the following organisms and their feeding relationships represented by arrows (pointing from the eaten to the eater): Grass (Producer) is eaten by Rabbit (Primary Consumer) and Organism X. Rabbit is eaten by Fox (Secondary Consumer). Organism X also eats Berries (Producer). Fox eats Organism X. Organism Y (Decomposer) consumes dead Organism X, Rabbit, and Fox. Organism W eats Fox. Ensure Organism X has arrows pointing from both Grass and Berries to it, and an arrow pointing from it to Fox. All labels should be clear. NO title, NO question text.
According to the food web provided, which organism functions as both a primary consumer and a secondary consumer?
Q24. (ID: ap_environmental_science_MCQ_U1S10Q24)
Which aquatic biome is characterized by brackish water, high productivity, and serves as a nursery for many marine species due to its unique mix of fresh and saltwater?
Q25. (ID: ap_environmental_science_MCQ_U1S10Q25)
Create a detailed and labeled diagram of the global nitrogen cycle. Show the main reservoirs (atmosphere, soil, biomass, water bodies) and key processes (nitrogen fixation, ammonification, nitrification, denitrification, assimilation). Use arrows to clearly indicate the flow of nitrogen compounds. Highlight the role of bacteria in various conversions. Ensure atmospheric nitrogen ($N_2$) and ammonia ($NH_3$) are labeled. NO title, NO question text.
The diagram illustrates the nitrogen cycle. Which step represents the conversion of atmospheric nitrogen ($N_2$) into ammonia ($NH_3$) or ammonium ($NH_4^+$) by bacteria?

Answer Key

1. A
2. C
3. B
4. A
5. B
6. D
7. C
8. A
9. B
10. D
11. C
12. C
13. B
14. A
15. C
16. A
17. A
18. A
19. B
20. A
21. B
22. C
23. A
24. D
25. A